[PATCH] vboxsf: Add __nonstring annotations for unterminated strings

[Kees Cook]

When a character array without a terminating NUL character has a static
initializer, GCC 15's -Wunterminated-string-initialization will only
warn if the array lacks the "nonstring" attribute[1]. Mark the arrays
with __nonstring to and correctly identify the char array as "not a C
string" and thereby eliminate the warning.

This effectively reverts the change in 4e7487245abc ("vboxsf: fix building
with GCC 15"), to add the annotation that has other uses (i.e. warning
if the string is ever used with C string APIs).

Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117178 [1]
Cc: Hans de Goede <hdegoede@xxxxxxxxxx>
Cc: Brahmajit Das <brahmajit.xyz@xxxxxxxxx>
Cc: Christian Brauner <brauner@xxxxxxxxxx>
Cc: linux-fsdevel@xxxxxxxxxxxxxxx
Signed-off-by: Kees Cook <kees@xxxxxxxxxx>
---
 fs/vboxsf/super.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/fs/vboxsf/super.c b/fs/vboxsf/super.c
index 1d94bb784108..0bc96ab6580b 100644
--- a/fs/vboxsf/super.c
+++ b/fs/vboxsf/super.c
@@ -21,8 +21,7 @@
 
 #define VBOXSF_SUPER_MAGIC 0x786f4256 /* 'VBox' little endian */
 
-static const unsigned char VBSF_MOUNT_SIGNATURE[4] = { '\000', '\377', '\376',
-						       '\375' };
+static const unsigned char VBSF_MOUNT_SIGNATURE[4] __nonstring = "\000\377\376\375";
 
 static int follow_symlinks;
 module_param(follow_symlinks, int, 0444);
-- 
2.34.1